RANs and WLANs are both wireless communication technologies. In a cellular RAN, the areas where the network is distributed are covered by cells, each served by at least one base station (commonly known as a NodeB in a 3G network and an eNodeB in an LTE/4G network). Mobile devices, known as User Equipment (UE), located within a cell connect to the telecommunications core network via the base station of the cell. Each cell typically abuts one or more neighbouring cells.
WLAN describes a wireless communication system in which coverage is provided over smaller areas. A common example is Wi-Fi, specified by the IEEE 802.11 standards. WLAN enabled devices can establish wireless links with WLAN Access points (APs) which then allow internet access. WLAN enabled devices can be mobile devices such as laptops, personal digital assistants and mobile phones, or fixed devices such as desktops and workstations that are equipped with a WLAN network interface. WLAN systems use the ISM radio band, a portion of the spectrum reserved internationally for industrial, scientific and medical purposes other than telecommunications. No fees or licences are needed for use of this band of the spectrum.
Various techniques have been considered for LTE-WLAN Aggregation (LWA) to allow a UE to connect with both a RAN and a WLAN for data communication. By aggregating data over both types of link the advantages of each system can be utilized in order to increase user throughput. Aggregating implies transmission of RAN based data over a WLAN connection. Transmission of data via two different routes creates the possibility that data sent via one route arrives out of sequence with data sent via the other route. WLAN transmission may be slower than RAN transmission due to contention-based access to radio resources, and the additional time required to forward data from the WLAN to the RAN. Data must thus be re-ordered at the RAN.
The examples described herein provide improved techniques for LTE-WLAN aggregation.
The examples described below are not limited to implementations which solve any or all of the disadvantages of known systems.